Case study, mapping sub-surface failure hazards - shallow mining tunnels  (Ipswich)

There are  numerous shallow mining tunnels in the old coal mining areas of east Ipswich, dating back to mining from 1880 – 1940. At this location, the main seam was the top Aberdare Seam as shallow as 10m. These tunnels cause sink-holes, subsidence and even failure. This figure presents a section where resistive areas (red) are interpreted as 'dry' tunnels conductive areas (blue) are interpreted as fluid conduits. Existing and possibly evolving sinkholes are inferred.

Case study, mapping aquifers for water bores (Sunshine Coast, Queensland)

Resistivity surveys are excellent in mapping low salinity aquifers. The resistivity of saline ground water and clay is substantially lower than low salinity ground water in sandy strata. In addition, measuring induced polarisation at the same time will assist in discriminating between fluids and clay.

This figure is a resistivity section close to a pre-existing water bore where the upper finer sediments in this meandering river environment have a lower resistivity then lower sandy strata (aquifer). The transition zone is mapped with assistance of induced polarisation (not shown).


PGC Geophysics operates an ABEM Terrameter LS2, 'Advanced 12/81', with up to 64 electrodes and up to 12 concurrent measurements. The system is capable of 600V and 2.5A, restricted to 250W.

The Terrameter LS2 and PGC Geophysics' survey equipment is suitable for high resolution measurements up to ~100m depth and records resistivity and IP data simultaneously. The equipment can be mobilised by 4WD or by road/air transport. 


Additional case studies and information, please download this informative flyer:

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